


Do No Harm

by S1D3S



Category: Shingeki no Kyojin | Attack on Titan
Genre: Angst, Canon-Typical Violence, Character Death, Developing Friendships, Enemies to Friends to Lovers, Eventual Happy Ending, Eventual Relationships, Eventual Romance, F/F, F/M, Friends to Lovers, Levi is going to get a friend that doesn't die even if it kills me, Mild Language, Poly Relationship, Polyamorous Character, Slight Canon Divergence, Slow Burn
Language: English
Status: In-Progress
Published: 2021-02-09
Updated: 2021-02-09
Packaged: 2021-03-15 02:54:00
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,945
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29306838
Author URL: https://archiveofourown.org/users/S1D3S/pseuds/S1D3S
Summary: Eriel Yeager's father once told her that as a doctor, she would have the choice of life and death in her hands; however, if Eriel should choose death, she must be certain because it cannot be undone. When she watches her world crash and burn before her eyes, she decides to join her brother and friends in enlisting in the military. Her medical skills passed down from her father come in handy when joining the Survey Corps. She's determined to keep her brother alive. Her childhood crush on her best friend comes back to haunt her in the middle of a war for humanity. As if that wasn't enough, this mysterious woman won't give her a moment of peace. She's really regretting taking a "Do No Harm" oath.
Relationships: Armin Arlert/Original Female Character(s), Armin Arlert/Original Female Character/Yelena (Shingeki no Kyojin), Yelena (Shingeki no Kyojin)/Original Character(s)
Kudos: 2





	Do No Harm

**Author's Note:**

> Hi!  
> Thank you for reading!  
> I want to start by explaining that "Do No Harm" will follow more of the manga than the anime. I am determined to give these poor traumatized kids a happy ending. Don't worry about spoilers because we are starting from the beginning. Yelena won't *physically* appear until much later. (I don't know why I did that to myself.) If I need to add any tags, please let me know!  
> Enjoy the story!

“Do you ever feel like something terrible is about to happen?” Eriel Yeager looked up to her parents from the book in front of her. She watched as her father placed his spoon back in the bowl before looking back at her. Her mother paused in her movements at the sink before quickly returning to the dishes. 

“Like what?” Grisha asked. 

Eriel shrugged. “I just got a feeling that something really bad is about to happen. Eren is with Mikasa, so he should be okay.” Eriel often had a way of knowing when her twin was up to no good and dragging their friends into it. 

Grisha ruffled her hair. “It’s just nerves. I’m taking you with me to the interior tomorrow so you can meet a friend of mine. It must be that.”

He wasn’t wrong. Unlike Eren, Eriel wanted to help people within the walls. She wanted to go to school and become a doctor like her father. To do that, she would need the help of her father’s commander friend. It was a lot of pressure on a 10-year-old. 

“Just keep studying, and you’ll do just fine.” Her mother chimed in. Carla winked back at Eriel. 

The door was kicked open with a sizable bang. Her brother and foster sister had returned and by the looks of it, Mikasa did all the work collecting firewood again. After putting away the wood, Eren plopped down next to his sister. His face was twisted into a disgusted pout.

As astounding as it was to be (what they assumed) the only twins in the city, Eren and Eriel were actually very different outside of looks. They had the same eyes, but Eriel’s were colder and less telling than her brothers. Where Eren was impulsive, Eriel was observant. Where Eriel was ruthless, Eren showed compassion. If we’re being honest, it frightened their parents sometimes. Eren was warm but consumed everything like a wildfire. Eriel was cold but destroyed only what was deemed necessary. Neither child forgave easily without some sort of compensation. 

“Mikasa stop you from fighting again?” she whispered to him. 

Eren grunted. “People were talking down about the scouts again.” He began eating the food placed in front of him before continuing. “They’re heroes. I don’t understand.” 

Eriel shrugged in reply, trying to stay as inconspicuous as possible in front of their parents. She admired the scouts as Eren did. She just didn’t believe the pros outweighed the cons when it came to exploring outside the walls. For all they knew, something far worse than titans was waiting for them. 

“Eren wants to join the scouts,” Mikasa announced. “He told Eriel, too.”

Their house went still for a moment. Eriel gaped at Mikasa from across the table. She really didn’t want to be dragged into this fight. 

“Mikasa!” Eren jumped from his seat, slamming his hands on the dining table. “I told you not to tell them!” 

“Eren!” Their mother turned Eren to face her. Kneeling down to his level, she kept a tight grip on him so he couldn’t turn away. “What are you thinking?! Do you know how many people died because they dared to venture outside the wall?”

Eriel decided to bury her head in her father’s book about medicinal herbs. It was safer than reminding her mother that she knew about Eren’s plan. 

“Eriel!” 

Well, she tried anyway. 

Eriel looked up from the inked pages. Carla was glaring at her from over Eren’s shoulders. “Why didn’t you say anything?! Don’t you know how dangerous this is?”

She flashed her mother an innocent smile, “Unlike Mikasa, I’m not a snitch. And Eren changes his mind about everything. I assumed he’d grow bored with the idea if we didn’t entertain it.”

“Not true!” Eren twisted in his mother’s grasp. “I will become a scout and go outside the walls!”

Eriel rolled her eyes. She went back to her book without a response. She really did believe her brother, but he was too stupid to realize she gave him a way out of their mother’s lecture. “Idiot.”

“Say it to my face-”

“Eren,” their father started, “why do you want to go outside?” He bent down to Eren’s level. Medical bag in hand, he was ready to leave, but Eriel assumed Eren’s determination was something to question. 

“I hate the idea of spending my whole life inside the wall, ignorant of what’s happening in the world outside!”

No one said anything for a moment. Eriel found herself agreeing with Eren for once the longer she thought about it. A part of her was curious about the world beyond but not enough to risk her life. The scouts always came back with more losses than any sort of gain. 

“I see.” Grisha trailed off for a second. He stood and continued his way to the door. “I’d better get going. The boat leaves soon and I have two patients to see in the interior.”

Eriel jumped from her seat, book in hand, ready to accompany him. He stopped her with his hand and a slight shake of his head. “But I always-”

“Not this time, Eri. I need you to stay here for today. Keep Eren out of trouble.” Grisha ruffled her hair once more and chucked as she struggled to fix it again. 

“Honey,” their mother looked between Grisha and Eren, “talk some sense into your son.”

He looked over his shoulder. “It doesn’t matter what anyone says. You can’t stop an inquisitive mind.” Grisha reached into his collar and pulled out a copper-colored key. Eren and Eriel looked at it in absolute wonder. “Eren, Eriel, when I get home, I’ll show you what I’ve been keeping a secret in the basement.”

“Really?” the twins voiced. They both wore matching faces of excitement. The mystery of the basement was their favorite topic to discuss. They would huddle together under a blanket while Mikasa and their parents were fast asleep whispering outlandish theories to each other. From their spots, the twins glanced at each other before grabbing hands and following their father on the porch. 

As they all waved Grisha off, Carla turned back to her son. “Eren, I won’t let you do anything foolish like join the survey corps.”

Eren looked at their mother sharply, yelling back, “The way I see it, people who are satisfied living like cattle are the real fools!”

Watching her brother run off, Eriel went back inside with a sigh. She grabbed the bag her mother made her from an old blanket and put a few bandages and a container of water inside along with the book she was reading. Throwing it over her shoulder, Eriel went out the door to follow Eren, seeing as Mikasa had already left. 

“Eriel.” Carla placed a soft hand on her youngest’s shoulder. She smiled as Eriel looked up at her. “Look after them, okay? I know you’re the youngest of you three, but I know you can do it. Don’t let Eren drag you two into too much trouble.”

Eriel grinned back at her mother. “You got it, mom!” And as she ran after her siblings, Eriel couldn’t help feeling like her mother was saying goodbye. The terrible feeling from earlier came back with a vengeance. 

“-and called me a heretic.” Eriel picked up Armin’s voice as she wandered closer to their usual spot by the river. She quickly glanced at her reflection in one of the nearby windows. Her hair was mildly in place and there wasn’t any food on her face. Taking a deep breath to mentally prepare herself for seeing Armin, she continued around the corner. 

“You can’t run off like that Eren.” She called out. “Mom was worried.”  
Eren waved her off. “They’re our lives. We can do what we want with them, right?”

“Absolutely not,” the girls chimed together. Eriel had taken a seat next to Armin, leaning on her knees to glare at her brother. Her face was slightly pink from being close to the blonde boy, but she convinced herself it was from the never-ending annoyance her brother caused. It was like a chronic plague she could never escape from. 

“That reminds me,” Eren turned to face Mikasa, “Thanks a lot for ratting me out to mom and dad!”

“Yeah! Me too! You didn’t have to drag me down with him!”

Mikasa glanced at both of them before looking back at the water, “I don’t recall agreeing to keep it a secret.” 

“How’d they take it?” Armin asked. 

“Of course, they weren’t pleased,” Eren answered.

“Well, dad didn’t exactly say no. But Armin,” Eriel faced the boy with a wide smile, “dad said he’d show us the basement when he gets home!”

Her excited smile caused the boy’s face to go pink. “That-That’s great!”

“I wonder if it has stuff about out-”

A loud boom interrupted the youngest Yeager. It shook the entire city, knocking the kids over. Eren and Armin stumbled to their feet while Eriel and Mikasa stayed on their knees. Eriel could feel her heart contract in her chest. Pain and fear melted through her body. Her dreadful feeling, her belief that something terrible was going to happen, just grew completely silent. 

“Let’s check it out.” Eren pulled his sister to her feet, not letting go of her wrist as they ran after Armin. “Armin, what is it…?”

Eriel’s gaze followed Armins to the mass of smoke rising from the other side of the wall. “Did they accidentally fire a cannon?” she asked herself. Any hope of an accident disappeared when a hand, a bright red hand with no skin, gripped the wall from the smoke. She stumbled back into her brother, who wrapped his arms around her instinctively. Both Yeager children seeking comfort in the other. 

“It can’t be,” Armin gasped next to her. “The-the wall is 50 meters high.” 

He was shaking next to Eriel. She gently wrapped her pinky around his. He wasn’t the only one scared. Her grip on his finger tightened when the titan lifted his head over the wall. She felt like it was looking right at them, like it knew they were scared. Armin squeezing back provided very little comfort. Eren’s arms shaking around her shoulders only solidified that this was reality. The growing murmurs surrounding the four were drowned out by a loud crackling boom as the titan kicked in the door. 

Eren yanked on Eriel, causing her to lose Armin’s hand, and burying her in his chest as debris scattered into the city. He kept her pinned as everyone else gaped at the hole in the wall that kept them safe for a century. 

Screams started off small before growing rapidly as people began to realize what was happening. Eriel looked at Eren. “Mom-”

They both took off in the opposite direction, towards the general direction of the fractured wall. Armin calling out after them. “Those pieces of the wall fell near the houses!” Eren shouted back. 

“Mom’s at home!” Eriel finished. 

“Mikasa!” Armin watches as the other girl joined them. 

The trio ducked into an alleyway close to their house. Eriel was reminding herself to not look around after spotting a body crushed under debris. “Just get home. Get home.” Her heart stopped as they rounded the corner and saw a piece of the wall pinning down their house. “Mommy!”

The trio began to pull away wood planks and smaller stones from the damaged home. Eriel’s sight was blurring with tears as she continued to come up empty. 

“Mom?” Eren questioned, revealing their mother trapped under the collapsed roof. 

“Eren? Eriel?” Her voice was a lot softer than they would’ve liked, but she was alive. She was pinned beneath a wooden beam. 

“Eri, grab that side. Mikasa, get that one.” Eren barked gripping on the beam. The girls followed his orders. “Move on three! One..two...three!” All three children summoned what strength they had and tried to lift the beam. It refused to budge. 

A heavy, rhythmic rumble halted their efforts. Eriel looked up to see titans walking the streets a decent distance away. She could feel herself begin to shake. Sending her brother a terrified look, she went back to trying to move the beam. 

“The titans,” their mother’s voice was quaking with terror, terror for her three children. “They got in, didn’t they?” No one answered. They didn’t have to. “Eren! Take Eriel and Mikasa and run!”

Eriel’s tears had finally run down her face. Unlike Eren, she was realistic. There was no way the four of them would make it together. They weren’t going to get this beam off by themselves. She stood there trying desperately to think of a plan that wouldn’t cost them their mother. 

“My legs got crushed by the rubble.” The hope drained from Eriel’s eyes completely. 

“I’ll carry you!” 

No. Eriel looked at Eren, still desperately trying to lift the beam with Mikasa. Eriel locked eyes with her mother. The tears doubled when she realized she was right. Their mother was lying, and Eren believed her. 

“Why don’t you ever listen to me?!” Carla’s eyes were flooded with tears. She had to look away from her youngest, who was too smart for her own good. She looked at Eren instead. ‘At least obey me this last time! Mikasa!”

Like Eriel, Mikasa had stopped pulling on the beam. She was crying excessively. 

All three went silent as a sing rhythmic boom sounded too close. Eriel glanced down the street to see a titan, blonde with a despairing smile stretched across its face, moved slowly towards them. It stood over the houses. Eriel had never even dreamed of something that big in her scariest nightmares. 

“You three! Get out of here!’ Carla cried. 

“Mikasa, Eriel, hurry up!” Despite her mother’s desperate plea, Eriel put all her strength into lifting the beam. The trio continued to try desperately. 

“Mr. Hannes!” Carla screamed. 

Eriel looked behind them for a moment. The drunk guard that always picked on them, that always teased Eren and helped them carry groceries from the market, had come for them. For a second, Eriel thought they’d be okay. Hannes could help lift the beam and get them out of there before the titan got too close. 

The sound of metal scraping together concerned Eriel. “ Wait! You mustn’t fight it!” her mother pleaded to the blonde man. Take the children and run!”

Eriel wanted to scream, to argue, to demand that she wouldn’t leave without her mother. She wasn’t ready to live without her yet. She refused to do so. “Mommy-”

Her mother looked at Eriel. She shook her head. It wasn’t worth the risk. Eriel and her siblings were worth so much more. 

An arm gripped around her waist, lifting her off the ground. Hannes had grabbed Mikasa’s hand and lifted Eren over his shoulder. He moved away from the rubble, from their mother. “Wait-wait, Mr. Hannes,” Eriel began to shout. “Our mother! We can’t leave her!” 

“What are you doing?!” Eren joined in. “Our mom is till-”

“Eren! Mikasa! Eriel!” their mother called out, interrupting Eren. “Survive! I love you!” 

Eriel couldn’t see her mother, and, in some ways, that was a blessing. Her memories of her mother wouldn’t be tarnished by watching her mother be devoured, by her mother’s blood. They would stay pristine, white, innocent. Unlike her brother’s, whose scream of terror was cut short by shock. 

Hannes continued to move through the streets as silently as possible with Mikasa trailing beside him and the Yeager twins in his hold. With nothing to keep her distracted, Eriel was forced to witness the mass of blood and bodies decorating the streets she and her friends played in. 

Suddenly, Eren began to hit Hannes. It caused him to drop both kids and let go of Mikasa. “Eren! What are you-?!”

“I could’ve saved her in another few seconds!” Eren began swinging at Hannes. “If you hadn’t been there-”

“We’d be dead.” Eriel caught her brother’s fist. She held it firmly but without trying to actively hurt him. “If Hannes hadn’t shown up, we’d all be dead. And that isn’t what Mom wanted.” She watched Eren’s eyes water just as hers were.

“You couldn’t save your mom,” Hannes stood behind Eriel. “Because you weren’t strong enough.” He continued as Eren struggled out of his twin’s grip. “I didn’t face the titan, because I wasn’t brave enough!”

Eriel turned around to see Hannes was also crying. He grabbed her hand and Eren’s. Reaching out to Mikasa and taking her hand, she continued forward. 

As they neared the dock, she could see soldiers tossing possessions in a pile off the boat. Without hesitation, she pulled Eren closer to her. She ripped off her bag and put it on Eren, hiding it under his brown jacket. “Mom made it. They aren’t taking it.” She whispered to him. She moved to stand closer, hiding the odd shape from the soldiers. When one went to reach for them to pull them apart, she screamed and clung on to Eren more. Mikasa doing the same. Pressed for time, the soldier let them on without a thought. Who would question the reactions of traumatized children anyway?

They settled together on the boat. Eriel holding on to both Eren and Mikasa as reality came crashing around her. Another shattering boom echoed in her ears as she witnessed another titan break through the gate. It busted through the way Eren always kicked open their front door: effortless. Eriel hid her face in Mikasa’s scarf as their boat moved away from the docks. She had enough of seeing bodies for one day.


End file.
